The subject matter disclosed herein relates generally to energy recovery systems.
In many closed loop expansion systems, a working fluid is heated to a temperature above its boiling point before being expanded to extract energy (work). A trilateral flash cycle, in contrast, is a thermodynamic cycle for extracting work from a heat source wherein the working fluid is heated to a temperature below its boiling point before being provided to a turbine (expander) to extract energy. During expansion, a large portion of the fluid (10-100%) typically flashes to a vapor state, causing a very large volume ratio (of volume flow per second at the exit over volume flow per second at the inlet). This volume ratio is problematic for all types of turbomachinery. Practically, the volume ratio (and hence pressure ratio) must be limited along with the work output. These constraints lower the thermodynamic efficiency when dealing with higher temperature waste heat.
It would be desirable to have an energy recovery system with higher power output and cycle efficiencies.